Image sensor and electronic device having the same

Abstract

An image sensor may include: a substrate including a substrate comprising a photoelectric conversion element; a pixel lens formed over the substrate and comprising a plurality of light condensing layers in which a lower layer has a larger area than an upper layer; a color filter layer covering the pixel lens; and an anti-reflection structure formed over the color filter layer.

What is claimed is: 
     
       1. An image sensor comprising:
 a substrate comprising a photoelectric conversion element; 
 a pixel lens formed over the substrate and comprising a plurality of light condensing layers in which a lower layer has a larger area than an upper layer; 
 a color filter layer covering an entire surface of the pixel lens; and 
 an anti-reflection structure formed over the color filter layer, wherein the anti-reflection structure prevents reflection of incident light, 
 wherein each of the plurality of light condensing layers has a flat surface, and the lower layer exposed by the upper layer has a smaller width than the wavelength of the incident light, and 
 wherein the upper layer has a smaller effective refractive index than the lower layer, and the upper layer and the lower layer are formed of a same material. 
 
     
     
       2. The image sensor of  claim 1 , further comprising:
 a focusing layer provided between the photoelectric conversion element and the pixel lens. 
 
     
     
       3. The image sensor of  claim 2 , wherein the focusing layer has a larger refractive index than the pixel lens. 
     
     
       4. The image sensor of  claim 2 , wherein the focusing layer has the same area as or a larger area than the pixel lens. 
     
     
       5. The image sensor of  claim 2 , wherein a focal distance between the pixel lens and the photoelectric conversion element is inversely proportional to the thickness of the focusing layer. 
     
     
       6. The image sensor of  claim 1 , wherein the pixel lens has a multilayer stepped structure. 
     
     
       7. The image sensor of  claim 1 , wherein the lower layer exposed by the upper layer has a smaller width than the wavelength of incident light which colors are separated through the color filter layer. 
     
     
       8. The image sensor of  claim 1 , wherein the plurality of light condensing layers have the same shape and are arranged in parallel to each other. 
     
     
       9. The image sensor of  claim 1 , wherein the upper layer has the same thickness as or a smaller thickness than the lower layer. 
     
     
       10. The image sensor of  claim 1 , wherein the upper layer has the same refractive index as or a smaller refractive index than the lower layer. 
     
     
       11. The image sensor of  claim 1 , further comprising:
 an anti-reflection layer formed over the pixel lens. 
 
     
     
       12. The image sensor of  claim 1 , wherein the color filter layer covers the entire surface of the pixel lens and has a flat top surface. 
     
     
       13. The image sensor of  claim 1 , wherein the color filter layer has a smaller refractive index than the pixel lens. 
     
     
       14. The image sensor of  claim 1 , wherein the anti-reflection structure comprises an anti-reflection layer or a hemispherical lens. 
     
     
       15. The image sensor of  claim 1 , wherein the color filter layer is contacted with the pixel lens. 
     
     
       16. An electronic device comprising:
 an optical system; 
 an image sensor suitable for receiving light from the optical system and comprising a pixel array in which a plurality of unit pixels are arranged in a matrix shape; and 
 a signal processing unit suitable for processing a signal outputted from the image sensor, 
 wherein each of the unit pixels comprises: 
 a substrate comprising a photoelectric conversion element; 
 a pixel lens formed over the substrate and comprising a plurality of light condensing layers in which a lower layer has a larger area than an upper layer; 
 a color filter layer covering an entire surface of the pixel lens; and 
 an anti-reflection structure formed over the color filter layer, wherein the anti-reflection structure prevents reflection of incident light, 
 wherein each of the plurality of light condensing layers has a flat surface, and the lower layer exposed by the upper layer has a smaller width than the wavelength of the incident light, and 
 wherein the upper layer has a smaller effective refractive index than the lower layer, and the upper layer and the lower layer are formed of a same material. 
 
     
     
       17. The electronic device of  claim 16 , further comprising:
 a focusing layer provided between the photoelectric conversion element and the pixel lens. 
 
     
     
       18. The electronic device of  claim 17 , wherein the focusing layer has a larger refractive index than the pixel lens, and
 wherein the color filter layer has a smaller refractive index than the pixel lens. 
 
     
     
       19. The electronic device of  claim 17 , wherein a focal distance between the pixel lens and the photoelectric conversion element is inversely proportional to the thickness of the focusing layer. 
     
     
       20. The image sensor of  claim 16 , wherein the color filter layer is contacted with the pixel lens.